Composite structures formed from laminated plies are typically designed to meet various requirements that may depend on the particular application. For example, in the aircraft industry, composite structures used to fabricate an airframe normally have minimum strength and stiffness requirements in order to meet performance and service life specifications. In designing such composite structures, it is often necessary to select the shape and orientation of the plies in order to provide adequate strength and stiffness in specific areas of the composite structure. The design process may rely heavily on the skill and experience of the designer to make the appropriate selections for the orientation, shape and the number of plies in order to assure that minimum performance criteria are met. In some cases, the design of laminated composite structures may consist of an iterative process in which various combinations of ply thicknesses and orientations are developed and tested before a final design meeting all performance requirements is selected. In some cases, the designer may specify a greater number of plies or thicker plies than is necessary to satisfy the minimum performance requirements. As a result, the current design process is not only time consuming, but may produce structural shapes that are not optimized for weight reduction.
Accordingly, there is a need for a method of optimizing the shapes of composite structures that result in minimum weight while meeting performance requirements, such as strength and stiffness.